package util;

public final class Pair<A extends Comparable<A>, B extends Comparable<B>> implements Comparable<Pair<A, B>> {
	public final A first;
	public final B second;

	public Pair(A first, B second) {
		super();
		this.first = first;
		this.second = second;
	}

	@Override
	public int compareTo(Pair<A, B> right) {
		int r;
		
		r = first.compareTo(right.first);
		if (r != 0) return r;
		
		r = second.compareTo(right.second);
		if (r != 0) return r;
		
		return 0;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((first == null) ? 0 : first.hashCode());
		result = prime * result + ((second == null) ? 0 : second.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj) return true;
		
		if (obj == null || getClass() != obj.getClass())  return false;
		
		@SuppressWarnings("unchecked")
		Pair<A, B> other = (Pair<A, B>) obj;
		
		if (first == null) {
			if (other.first != null)
				return false;
		} else if (!first.equals(other.first))
			return false;
		
		if (second == null) {
			if (other.second != null)
				return false;
		} else if (!second.equals(other.second))
			return false;
		
		return true;
	}

}